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Subject: RE: [xri] Potential breakthrough
I wrote:
> To answer this question, I
would ask the following: Can we identify a parser
> client
who's use case is not satisfied by the 2.0 abstract
syntax?
Drummon, bbviously, you have one in the form of the
XDI-RDF-processor-as-client. We should explore precisely why this use case isn't
satisfied by 2.0 abstract syntax.
~
Steve
From: Steven Churchill [mailto:steven.churchill@xdi.org] Sent: Wednesday, May 02, 2007 3:14 PM To: 'Drummond Reed'; xri@lists.oasis-open.org Subject: RE: [xri] Potential breakthrough Drummond,
I think the best
approach at this point is to address the 100 lb gorilla issue head
on:
100 lb gorilla issue: Should we be changing the
2.0 abstract syntax?
[Note that this question exists with or without the
compact syntax, because the compact syntax can be normalized, if we so
decide, to the 2.0 abstract syntax.]
To answer this question, I would ask the following:
Can we identify a parser client who's use case is not satisfied by the
2.0 abstract syntax?
[If we take the approach of working from the ABNF up,
then we are still going to need to confront the gorilla issue at some later
time.]
~ Steve
From: Drummond Reed [mailto:drummond.reed@cordance.net] Sent: Wednesday, May 02, 2007 8:51 AM To: xri@lists.oasis-open.org Subject: [xri] Potential breakthrough I have an internal maxim that I
follow: if Steve tells me he’s got a problem with something, and after three
times trying to work it out with him, he’s still got a problem with it, then I
need to look at it very closely and see if there’s a better
solution. I’ve worked long enough with Marty
now to realize the same thing is true with him. So when both of them plus Wil are
telling me something is too complex, that’s one helluva strong
signal. So after yesterday’s thread, I
looked closely at the requirements again and thought about the key issue Steve
has raised about how “sticky stars” makes for funky synonym rules. This jibes
with what Marty keeps saying about how the original “compact syntax” was much
simpler than “sticky stars”. I have always been the one saying
that we needed sticky stars. So I revisited that assumption…and realized that in
that area I too had been stuck with a “2.0” filter on. I had been assuming that
anything you could express as a parenthetical xref (which is “opaque” to XRI
resolution) had to be something that was also equally “opaque” when expressed as
a global-xref. But it’s that assumption that leads
both to most of the increased complexity and the funky synonym problem. So if
you drop that assumption and do as Marty has been suggesting all along and
simply treat all subsegments as subsegments… …everything works just
fine. To illustrate, take Steve’s
@ootao+west*steve and @ootao*west*steve example. The current 2.1 syntax proposal
requires these parse into separate trees: @ ootao +west*steve @ ootao *west *steve But if you drop the requirement that
global-xrefs need to be syntactically opaque, they would both parse into the
same trees, with the only difference being the type of one
subsegment: @ ootao +west *steve @ ootao *west *steve The funky synonym problem goes away
because all subsegments are subsegments, and if @ootao wants to declare +west
and *west as synonyms, it doesn’t affect any other synonyms lower in the tree.
But you still get the semantic precision of @ootao being able to express that
+west is intended to be a generic dictionary identifier vs. *west a local name
without any expectation of cross-referencability. So I tried to figure out if there
was any other requirement – in XDI RDF or anywhere else global-xrefs would be
used – that would not be met if global-xrefs were not opaque. I couldn’t come up
with any. If so, we could essentially have our
cake and eat it too. The ABNF would get significantly simpler, and we’d get all
the semantic simplicity/richness of direct concatenation, but without any of the
pain of funky synonyms or increase resolution
complexity. Frankly, I’m still trying to figure
out why I was so stuck on “sticky stars” (so to speak ;-). After all, Marty has
repeatedly said things would be much simpler without them. But then, sometimes
when something’s stuck in your head, it takes a real jolt to knock it
out. I’ll take a pass on the simpler ABNF
that reflects all this as soon as I get a break today – worst case I’ll try to
have something published by tonight. =Drummond
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